1. Field of the Invention
The present invention relates to a display apparatus and a control method thereof.
2. Description of the Related Art
Liquid crystal panels used in liquid crystal display apparatuses display images by changing the transmittance of light emitted from a backlight. One problem in liquid crystal display apparatuses is that poor reproduction of blacks is caused by leaking of light of the backlight from the liquid crystal panel.
Attention has been drawn to a technique which dynamically adjusts the emission brightness of the backlight in accordance with input image signals to deal with this problem in liquid crystal display apparatuses. With this technique, the reproduction of blacks can be improved by adjusting (lowering) the emission brightness of the entire backlight when the brightness level of an input image signal is low.
Liquid crystal display apparatuses typically include a function for displaying an OSD (On Screen Display) image such as a menu image. If, however, an OSD image is displayed with the emission brightness of the backlight being lowered in accordance with the input image signal as mentioned above, the OSD image will be displayed darkly, resulting in poor visibility of the OSD image.
Conventional techniques intended to solve such a problem include an image display apparatus proposed by Japanese Patent Application Laid-open No. 2005-321424, in which the emission brightness of the entire backlight is maintained at a certain level when an OSD image is displayed.
Another image display apparatus proposed by Japanese Patent Application Laid-open No. 2008-299191 controls the emission brightness of the entire backlight to be kept higher than a predetermined level when an OSD image is displayed.